PT-2026-42635 · Packagist · Twig/Twig

Published

2026-05-21

·

Updated

2026-05-21

CVSS v4.0

8.7

High

VectorAV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Description

The object-destructuring assignment syntax introduced in Twig 3.24.0 generates a call to CoreExtension::getAttribute() with the $sandboxed argument hardcoded to false, regardless of whether a SandboxExtension is active. This permanently disables the sandbox's property and method policy checks for every destructuring expression.
ObjectDestructuringSetBinary::compile() emits:
CoreExtension::getAttribute($this->env, $this->source, ..., TwigTemplate::ANY CALL, false, false, false, ...);
//                                        ^^^^^
//                                    sandbox check never runs
Whereas GetAttrExpression::compile() correctly passes $env->hasExtension(SandboxExtension::class).
An attacker with write access to a sandboxed Twig template can read any public property or invoke any public getter on objects passed to the template engine, bypassing SecurityPolicy restrictions. The exploit requires only the {% do %} tag to be in allowedTags, which is a common configuration.

Resolution

The destructuring compiler now forwards the active sandbox flag to getAttribute() so property/method allowlists are enforced.

Credits

Twig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting and fixing the issue.

Exploit

Fix

Protection Mechanism Failure

Weakness Enumeration

CWE-693

Related Identifiers

GHSA-MM6W-GR99-P3JJ

Affected Products

Twig/Twig